The deluge of money flooding into passive investments can swing stock prices, but fears of widespread market disruptions are overblown, according to a new report from S&P Global.

Investors yanking cash out of index-tracking strategies exacerbated sharp declines in early February, when stocks plunged and volatility surged, according to the report from S&P Global Market Intelligence, the data and research arm of the company behind the indexing business that includes the popular S&P 500 stock index.